Heat exchanger

ABSTRACT

The present invention relates to a heat exchanger that can enhance thermal efficiency by enabling combustion heat of combustion gas generated by the combustion of a burner to be maximally returned to a heating medium, the heat exchanger being provided with a heat exchange unit having heating medium flow channels through which a heating medium flows and combustion gas flow channels through which combustion gas combusted in the burner flows to be alternately formed and adjacent to each other in spaces between a plurality of plates, wherein the heat exchange unit comprises: a sensible heat unit which surrounds the outer side of a combustion chamber, is formed of one side area of the plates, and heats the heating medium by using sensible heat of combustion gas generated by the combustion of the burner; and a latent heat unit which is formed of the other side area of the plates, and heats the heating medium by using latent heat of water vapor included in combustion gas that has finished undergoing heat exchange in the sensible heat unit, wherein a flow channel cap is coupled to the rear of the sensible heat unit so as to provide a flow channel for combustion gas in order to enable combustion gas that passed through the combustion gas flow channels formed on the upper part of the sensible heat unit to enter into the combustion gas flow channels of the latent heat unit.

TECHNICAL FIELD

The present invention relates to a heat exchanger, and moreparticularly, to a heat exchanger having a simplified assembly structureby stacking a plurality of plates to integrally form a sensible heatunit and a latent heat unit, and also capable of improving heat exchangeefficiency by effectively recovering heat radiated from a combustionchamber.

BACKGROUND ART

A boiler used for heating or warm water is a device configured to heat adesired area or supply warm water by heating water or direct water(hereinafter referred to as a “heating medium”) being heated by a heatsource, and the boiler is configured to include a burner configured tocombust a mixture of a gas and air and a heat exchanger configured totransfer combustion heat of a combustion gas to the heating medium.

A boiler produced in an early stage uses a heat exchanger which heats aheating medium using only sensible heat generated when a burner performsa combustion operation, but a condensing boiler, which has a sensibleheat exchanger configured to absorb sensible heat of a combustion gasgenerated in a combustion chamber, and a latent heat exchangerconfigured to absorb latent heat generated by condensation of watervapor contained in the combustion gas which underwent heat exchange inthe sensible heat exchanger, is recently being used to improve thermalefficiency. Such a condensing boiler is being applied to an oil boileras well as a gas boiler, thereby contributing to an increase in boilerefficiency and a reduction in fuel cost.

As described above, a conventional condensing type heat exchangerincluding a sensible heat exchanger and a latent heat exchanger isconfigured with a structure in which a blower, a fuel supply nozzle, anda burner are installed above a housing, and the sensible heat exchangerand the latent heat exchanger, which each have a heat exchange fincoupled to an outer side of a heat exchange pipe, are sequentiallyinstalled inside the housing below the burner.

However, in the conventional condensing type heat exchanger, there is aproblem in that a volume of the heat exchanger is increased due to theblower being disposed above the housing and the structures of thesensible heat exchanger and the latent heat exchanger which areindividually installed inside the housing.

As a prior art for improving heat exchange efficiency and minimizing avolume while resolving such a problem, Korean Registered Patent Nos.10-1321708 and 10-0813807 each disclose a heat exchanger configured witha burner disposed at a central portion of the heat exchanger, and a heatexchange pipe wound around a circumference of the burner in the form ofa coil.

In each of the heat exchangers disclosed in the above-described patents,a combustion gas generated by combustion of the burner passes through avertically separated space of heat exchange pipes and flows through aspace between the heat exchange pipes and an inner wall of a housing,and thus heat transferred to the housing is totally dissipated to anouter side of the housing such that there is a problem in that the heatof the combustion gas cannot be sufficiently transferred to a heatingmedium flowing inside the heat exchange pipes.

Further, the conventional heat exchanger has a structural limitation inthat a flow channel of the heating medium is short, and thus a heattransfer area between the heating medium and combustion gas cannot bewidely secured.

DISCLOSURE Technical Problem

The present invention has been proposed to resolve the above-mentionedproblems, and it is an objective of the present invention to provide aheat exchanger capable of improving thermal efficiency by allowingcombustion heat of a combustion gas generated by combustion of a burnerto be maximally recovered by a heating medium.

It is another objective of the present invention to provide a heatexchanger capable of maximizing heat exchange efficiency between aheating medium and a combustion gas while securing a large heat transferarea between the heating medium and the combustion gas due to a flowchannel of the heating medium being formed to be long in a limitedspace.

Technical Solution

To achieve the above-described objectives, a heat exchanger of thepresent invention a heat exchanger including a heat exchange unit (200)in which heating medium flow channels through which a heating mediumflows in a space between a plurality of plates and combustion gas flowchannels through which a combustion gas combusted in a burner (100)flows are alternately formed to be adjacent to each other, wherein theheat exchange unit (200) is configured with a sensible heat unit (200A)configured to surround an outer side of a combustion chamber (C),configured with an area at one side of a plate, and configured to heatthe heating medium using sensible heat of the combustion gas generatedby combustion of the burner (100); and a latent heat unit (200B)configured with an area at the other side of the plate and configured toheat the heating medium using latent heat of water vapor contained inthe combustion gas which undergoes heat exchange in the sensible heatunit (200A), and a flow channel cap (400) is coupled to a rear side ofthe sensible heat unit (200A), and configured to provide a flow channelof the combustion gas to allow a combustion gas which passes through acombustion gas flow channel formed at an upper portion of the sensibleheat unit (200A) to flow into a combustion gas flow channel of thelatent heat unit (200B).

Advantageous Effects

In accordance with a heat exchanger of the present invention, a flowchannel cap configured to provide a bypass flow channel of a combustiongas, which is generated by combustion of a burner, is provided behind asensible heat unit to allow the combustion gas which passes a combustiongas flow channel formed at an upper portion of the sensible heat unit toflow in a combustion gas flow channel of a latent heat unit so thatcombustion heat of the combustion gas can be maximally recovered by aheating medium such that thermal efficiency can be improved.

Further, a latent heat unit having multiple parallel heating medium flowchannels and a sensible heat unit having serial heating medium flowchannels are integrally formed by stacking a plurality of unit platesmanufactured in a similar pattern, and thus a flow channel of theheating medium is formed to be maximally long in a limited space suchthat heat exchange efficiency between the heating medium and thecombustion gas can be maximized.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a heat exchanger according to oneembodiment of the present invention.

FIG. 2 is a right side view of the heat exchanger according to oneembodiment of the present invention.

FIG. 3 is a front view of the heat exchanger according to one embodimentof the present invention.

FIG. 4 is an exploded perspective view of the heat exchanger accordingto one embodiment of the present invention.

FIG. 5 is an enlarged perspective view of a portion of a unit plateshown in FIG. 4.

FIG. 6 is a perspective view illustrating a flow channel of a heatingmedium passing through a latent heat unit and a sensible heat unit.

FIG. 7 is a perspective view taken along line A-A of FIG. 3.

FIG. 8 is a perspective view taken along line B-B of FIG. 3.

FIG. 9 is a perspective view taken along line C-C of FIG. 3.

FIG. 10 is a perspective view taken along line D-D of FIG. 3.

FIG. 11 is a perspective view taken along line E-E of FIG. 3.

FIG. 12 is a perspective view taken along line F-F of FIG. 3.

FIG. 13 is a perspective view taken along line G-G of FIG. 3.

FIG. 14 is a perspective view taken along line H-H of FIG. 3.

FIG. 15 is a perspective view taken along line I-I of FIG. 3.

FIG. 16 is a perspective view illustrating a state in which a combustiongas pass-through unit is formed at a lower portion of the latent heatunit.

FIG. 17 is a diagram illustrating a state in which a heating medium isguided in a direction toward an inner side of a combustion chamber by aguide unit.

** Description of Reference Numerals ** 1 and 1′: heat exchangers 100:burner 200: heat exchange unit 200A: sensible heat unit 200B: latentheat unit 200B-1: first latent heat unit 200B-2: second latent heat unit200-1 to 200-12: unit plates 200A-1 to 200a-12: first plates 200b-1 to200b-12: second plates 200-A: first plate group 200-B: second plategroup 200-C: third plate group 201: heating medium inlet 202: heatingmedium outlet 203: first combustion gas flow hole 204: second combustiongas flow hole 210: first plane portion 220: first protrusion 221: firstguide unit 222: first gap maintaining portion 230: second protrusion240: first flange 241: first incised portion 250: second plane portion260: first recess 261: second guide unit 262: second gap maintainingportion 270: second recess 280: second flange 281: second incisedportion 290: heating medium blocking unit 300: combustion gas dischargeunit 310: lower cover 311: condensation discharge pipe 320: combustiongas discharge pipe 400: flow channel cap 400a: combustion gas bypassflow channel A1: first opening A2: second opening B: water housingcooling unit B1: first insulating plate B2: second insulating plate C:combustion chamber D: combustion gas pass-through unit H1 to H8:through-holes H3′ and H7′: first blocked portions H4′ and H8′: secondblocked portions H3-1 and H4-1: first flanges H7-1 and H8-1: secondflanges P1: latent heat unit heating medium flow channel P2: latent heatunit combustion gas flow channel P3: sensible heat unit heating mediumflow channel P4: sensible heat unit combustion gas flow channel

MODES OF THE INVENTION

Hereinafter, configurations and operations for preferred embodiments ofthe present invention will be described in detail with reference to theaccompanying drawings.

Referring to FIGS. 1 to 6, a heat exchanger 1 according to oneembodiment of the present invention includes a burner 100 configured tocombust a mixture of air and fuel to generate combustion heat and acombustion gas; a heat exchange unit 200 provided at a circumference ofthe burner 100 to perform a heat exchange between a heating medium andthe combustion gas generated by the combustion in the burner 100, andhaving a sensible heat unit 200A and a latent heat unit 200B which areintegrally formed by stacking a plurality of plates; a combustion gasdischarge unit 300 configured to discharge a combustion gas which passesthrough the heat exchange unit 200; and a flow channel cap 400 providedbehind the sensible heat unit 200A and configured to provide a flowchannel of the combustion gas to allow a combustion gas which passesthrough a combustion gas flow channel formed at an upper portion of thesensible heat unit 200A to flow into a combustion gas flow channel ofthe latent heat unit 200B.

The burner 100 is a cylindrical burner and is assembled by beinginserted into a space of a combustion chamber C provided at the heatexchange unit 200 in a horizontal direction from a front surface,thereby improving convenience of detaching the burner 100 andmaintenance work of the heat exchanger 1.

The heat exchange unit 200 is configured with a sensible heat unit 200Aconfigured to surround an outer side of the combustion chamber C to formone side region of each of the plurality of plates, and heat the heatingmedium using sensible heat of the combustion gas generated by thecombustion of the burner 100; and a latent heat unit 200B configured tofrom another side region of each of the plurality of plates, and heatthe heating medium using latent heat generated when water vaporcontained in the combustion gas which undergoes heat exchange in thesensible heat unit 200A is condensed.

The plurality of plates are disposed in an upright structure and stackedin a front-rear direction to allow the sensible heat unit 200A to bedisposed at an upper portion and the latent heat unit 200B to bedisposed at a lower portion.

The combustion gas discharge unit 300 is configured with a lower cover310 configured to cover a lower portion of the latent heat unit 200B,and a combustion gas discharge pipe 320 having a side connected to thelower cover 310 and extending upward. A condensation discharge pipe 311configured to discharge condensation generated at the latent heat unit200B is connected to a lower portion of the lower cover 310.

The flow channel cap 400 is coupled to a rear side of the plurality ofstacked plates to form a combustion gas bypass flow channel 400 abetween the rear side and the flow channel cap 400, and while an examplein which the flow channel cap 400 is formed in a plate shape is shown inthe present embodiment, the shape of the flow channel cap 400 can beconfigured different from the plate shape.

Configurations and operations of the plurality of plates, the sensibleheat unit 200A, and the latent heat unit 200B, which constitute the heatexchange unit 200, will be described below.

The heat exchange unit 200 is configured such that the plurality ofplates are stacked from a front side to a rear side, and the sensibleheat unit 200A disposed at the upper portion and the latent heat unit200B disposed at the lower portion are integrally formed with theplurality of plates.

As one example, the plurality of plates may be configured with first totwelfth unit plates 200-1, 200-2, 200-3, 200-4, 200-5, 200-6, 200-7,200-8, 200-9, 200-10, 200-11, and 200-12, and the first to twelfth unitplates are configured with first plates 200 a-1, 200 a-2, 200 a-3, 200a-4, 200 a-5, 200 a-6, 200 a-7, 200 a-8, 200 a-9, 200 a-10, 200 a-11,and 200 a-12, which are disposed at front sides of the unit plates, andsecond plates 200 b-1, 200 b-2, 200 b-3, 200 b-4, 200 b-5, 200 b-6, 200b-7, 200 b-8, 200 b-9, 200 b-10, 200 b-11, and 200 b-12, which aredisposed at back sides of the unit plates.

Referring to FIGS. 7 to 13, a latent heat unit heating medium flowchannel P1 and a sensible heat unit heating medium flow channel P3 areformed between the first plate and the second plate constituting each ofthe unit plates, and a latent heat unit combustion gas flow channel P2and a sensible heat unit combustion gas flow channel P4 are formedbetween a second plate constituting a unit plate disposed at one side ofadjacently stacked unit plates and a first plate constituting a unitplate disposed at the other side thereof.

Referring to FIGS. 4 and 5, the first plate is configured with a firstplane portion 210; a first protrusion 220 protruding from one side ofthe first plane portion 210 toward the front side, having a centralportion at which a first opening portion A1 is formed, and configured toconstitute the sensible heat unit 200A; a second protrusion 230protruding from the other side of the first plane portion 210 toward thefront side and configured to form the latent heat unit 200B; and a firstflange 240 bent from an edge of the first plate toward the rear side.

In the first plate 200 a-1 disposed at the foremost position of thefirst plate, a heating medium inlet 201 is formed at one side of a lowerportion of the latent heat unit 200B, and a heating medium outlet 202 isformed at one side of an upper portion of the sensible heat unit 200A.

In the first plates 200 a-2 to 200 a-12 of the first plates, which aresequentially stacked behind the first plate 200 a-1 disposed at theforemost position, a first through-hole H1 is formed at the one side ofthe lower portion of the latent heat unit 200B, a second through-hole H2is formed at one side of an upper portion of the latent heat unit 200B,a third through-hole H3 is formed at one side of a lower portion of thesensible heat unit 200A, and a fourth through-hole H4 is formed at theother side of the upper portion of the sensible heat unit 200 A.

The second plate is configured with a second plane portion 250; a firstrecess 260 recessed from one side of the second plane portion 250 to therear side, having a central portion at which a second opening A2corresponding to the first opening A1 is formed, and configured to formthe sensible heat unit heating medium flow channel P3 between the firstprotrusion 220 and the first recess 260; a second recess 270 recessedfrom the other side of the second plane portion 250 to the rear side,and configured to form the latent heat unit heating medium flow channelP1 between the second protrusion 230 and the second recess 270; and asecond flange 280 bent from an edge of the second plate to the rearside.

In the second plate, a fifth through-hole H5 is formed at the one sideof the lower portion of the latent heat unit 200B, a sixth through-holeH6 is formed at the one side of the upper portion of the latent heatunit 200B, a seventh through-hole H7 is formed at the one side of thelower portion of the sensible heat unit 200A, and an eighth through-holeH8 is formed at the other side of the upper portion of the sensible heatunit 200A.

Further, first blocked portions H3′ and H7′ are respectively formed atthe other side of the lower portion of the sensible heat unit 200A inthe first plate 200 a-9 of the ninth unit plate 200-9 and the secondplate 200 b-8 of the eighth unit plate 200-8, and second blockedportions H4′ and H8′ are respectively formed at the one side of theupper portion of the sensible heat unit 200A in the first plate 200 a-5of the fifth unit plate 200-5 and the second plate 200 b-4 of the fourthunit plate 200-4. The first blocked portions H3′ and H7′ and the secondblocked portions H4′ and H8′ are configured to change a flow channel ofthe heating medium passing through the sensible heat unit heating mediumflow channel P3 to form a serial flow channel, and operations thereofwill be described below.

Further, in the plates 200 b-1 to 200 b-12 stacked behind the firstplate 200 a-1 which is disposed at the foremost position, a plurality offirst combustion gas flow holes 203 are formed the upper portion of thesensible heat unit 200A and a plurality of second combustion gas flowholes 204 are formed at the lower portion of the sensible heat unit200A. The plurality of first combustion gas flow holes 203 provide flowchannels through which the combustion gas generated in the combustionchamber C flows to the combustion gas bypass flow channel 400 a formedbetween the sensible heat unit 200A and the flow channel cap 400, andthe plurality of second combustion gas flow holes 204 provide flowchannels through which the combustion gas which passes through thecombustion gas bypass flow channel 400 a flows to the combustion gasflow channel of the latent heat unit 200B.

Meanwhile, referring to FIGS. 10 and 13, first flanges H3-1 and H4-1 arerespectively formed at the through-holes H3 and H4 to protrude towardthe sensible heat unit combustion gas flow channel P4, and secondflanges H7-1 and H8-1 are respectively formed at the through-holes H7and H8 to protrude toward the sensible heat unit combustion gas flowchannel P4 to be in contact with ends of the first flanges H3-1 andH4-1.

According to the configurations of the first flanges H3-1 and H4-1 andthe second flanges H7-1 and H8-1, the sensible heat unit heating mediumflow channel P3 and the sensible heat unit combustion gas flow channelP4 are spatially separated and a gap between the sensible heat unitheating medium flow channel P3 and the sensible heat unit combustion gasflow channel P4 may also be constantly maintained.

Further, referring to FIGS. 4 and 15, a water housing cooling unit Bconfigured to provide a heating medium connecting flow channel to allowthe heating medium which passes through the heating medium flow channelof the latent heat unit 200B to flow into the heating medium flowchannel of the sensible heat unit 200A and insulate the combustionchamber C is formed behind the sensible heat unit 200A.

The water housing cooling unit B is configured such that the heatingmedium is filled in a space between a first insulating plate B1 formedat the first plate 200 a-12 of the unit plate 200-12 disposed at therearmost position, and a second insulating plate B2 formed at the secondplate 200 b-12 of the unit plate 200-12. Protrusions and recesses, whicheach have a comb shape, may be formed to intersect each other on thefirst insulating plate B1 and the second insulating plate B2, and thusturbulence is generated in a flow of the heating medium passing throughthe water housing cooling unit B.

According to the configuration of the water housing cooling unit B, heatinsulation of the combustion chamber C is possible without separateinsulation being installed to prevent overheating of the heat exchanger1, and thus a heating medium connecting flow channel configured toconnect the latent heat unit heating medium flow channel P1 and thesensible heat unit heating medium flow channel P3 may be widely securedin a space between the first insulating plate B1 and the secondinsulating plate B2 such that flow channel resistance of the heatingmedium can be reduced. Further, the sensible heat unit heating mediumflow channel P3 through which the heating medium flows is provided at anouter wall surrounding the combustion chamber C and thus heat insulationof the outer wall of the combustion chamber C is possible such that theheat insulation of the combustion chamber C may be achieved over anentire area thereof by the water housing cooling unit B and the sensibleheat unit heating medium flow channel P3.

Meanwhile, the second protrusion 230 and the second recess 270 may beformed in comb shapes bent in opposite directions. In this case, whenthe first plate and the second plate are stacked, the first planeportion 210 and the second plane portion 250 are in contact, the latentheat unit heating medium flow channel P1 through which the heatingmedium flows is formed between the second protrusion 230 and the secondrecess 270 which are bent in the opposite directions in one unit plate,and the latent heat unit combustion gas flow channel P2 through whichthe combustion gas flows is formed between the second recess 270 of oneof adjacently stacked unit plates and a second protrusion 230 of theother thereof.

As described above, the second protrusion 230 and the second recess 270are configured to be in comb shapes bent in opposite directions, andthus turbulence is generated in a flow of the heating medium passingthrough the latent heat unit heating medium flow channel P1 and in aflow of the combustion gas passing through the latent heat unitcombustion gas flow channel P2 such that heat exchange efficiency can beincreased.

Referring to FIGS. 7 and 16, when the first plate and the second plateare stacked, the first flange 240 and the second flange 280 partiallyoverlap each other, and the overlapping portions are weld-coupled suchthat an outer wall of the heat exchange unit 200 is formed.

Further, in a state in which the first flange 240 and the second flange280 of adjacent plates overlap, a combustion gas pass-through unit Dthrough which the combustion gas flowing in the latent heat unitcombustion gas flow channel P2 passes toward the combustion gasdischarge unit 300 is formed at some portions of the plurality ofplates.

To this end, a plurality of first incised portions 241 are formed at acombustion gas discharge side of the first flange 240, a plurality ofsecond incised portions 281 are formed at a combustion gas dischargeside of the second flange 280, and the combustion gas pass-through unitD is formed at some portions of the first incised portion 241 and thesecond incised portion 281 when the first plate and the second plate arestacked.

The combustion gas pass-through unit D is formed at the lower portion ofthe latent heat unit 200B to be spaced a predetermined distance apartfrom the latent heat unit 200B in a lateral direction and a longitudinaldirection, and thus the combustion gas which passes through the latentheat unit 200B may be distributed and discharged at a uniform flow rateacross an entire area of the latent heat unit 200B such that thecombustion gas pass-through unit D serves to prevent noise and vibrationand reduce flow resistance of the combustion gas passing through thelatent heat unit 200B and discharged to the combustion gas dischargeunit 300.

Meanwhile, guide units 221 and 261 configured to guide the heatingmedium to flow toward the center of the combustion chamber C are formedat the heating medium flow channel P3 of the sensible heat unit 200A. Aplurality of guide units 221 and a plurality of guide units 261 areformed and spaced apart from each other at an outer side portion of thesensible heat unit 200A in a circumferential direction thereof.

Here, the outer side portion of the sensible heat unit 200A is an areabetween an intermediate portion and an outer end of the sensible heatunit 200A in a width direction, and refers to an area adjacent to theouter end thereof.

The guide units 221 and 261 include the plurality of first guide units221 protruding from the first plate toward the sensible heat unitheating medium flow channel P3, and the plurality of second guide units261 protruding from the second plate toward the sensible heat unitheating medium flow channel P3 and formed at positions corresponding tothe plurality of guide units 221.

Referring to FIGS. 11 and 17, a protruding end of the first guide unit221 and a protruding end of the second guide unit 261 are in contactwith each other to enhance coupling strength between the first plate andthe second plate.

The first guide unit 221 may be configured with a first guide 221 adisposed on a front side on the basis of a flow direction of the heatingmedium, a second guide 221 b disposed to be spaced in a diagonaldirection from a rear side of the first guide 221 a toward thecombustion chamber C, and a third guide 221 c disposed to be spacedapart from a rear side of the guide 221 a, and the second guide unit 261may also be configured to correspond to the first guide unit 221.

With such configurations of the guide units 221 and 261, as indicated byarrows in FIG. 17, since a flow channel of the heating medium flowingalong the sensible heat unit heating medium flow channel P3 is guided bythe guide units 221 and 261 in a direction toward the combustion chamberC, a distance between the burner 100 installed inside the combustionchamber C and the heating medium is shortened such that the combustionheat of the burner 100 can be effectively transferred to the heatingmedium, and generation of turbulence is promoted in the flow of theheating medium such that heat transfer efficiency can be improved.

Referring to FIG. 12, a plurality of first gap maintaining portions 222protruding toward the sensible heat unit combustion gas flow channel P4are formed at the first protrusion 220, and a plurality of second gapmaintaining portions 262 are formed at the first recess 260 at positionscorresponding to the plurality of first gap maintaining portions 222 toprotrude toward the sensible heat unit combustion gas flow channel P4. Aprotruding end of the first gap maintaining portion 222 and a protrudingend of the second gap maintaining portion 262 are formed to be incontact with each other.

With such configurations of the first gap maintaining portion 222 andthe second gap maintaining portion 262, a gap of the sensible heat unitcombustion gas flow channel P4 may be constantly maintained, and thecoupling strength between the first plate and the second plate may beenhanced in association with the above-described configurations of thefirst flanges H3-1 and H4-1 and the second flanges H7-1 and H8-1.

Meanwhile, in order to form a local laminar flow in the combustion gasflowing through the sensible heat unit combustion gas flow channel P4 toimprove heat exchange efficiency between the combustion gas and theheating medium, a gap, which is a vertically spaced distance, of thesensible heat unit combustion gas flow channel P4 is preferably set tobe in a range of 0.8 to 1.6 mm.

Further, as shown in FIGS. 11, 12, and 15, one of the ends of the firstplate and the second plate, which are disposed at a circumference of thecombustion chamber C, is bent, seamed, and weld-coupled to be in closecontact with the other end. In this case, a length of a seamed end S ofthe first plate and the second plate is preferably set to be in a rangeof 1 to 5 mm to prevent overheating of the seamed end S and maintainwelding quality.

Meanwhile, referring to FIG. 17, a width E1 of a side area facing thelatent heat unit 200B is preferably formed to be greater than a width E2of a side area opposite the latent heat unit 200B among areas of theplate constituting the sensible heat unit 200A. This is because most ofthe combustion gas generated in the combustion chamber C flows towardthe latent heat unit 200B and thus the width E1 of the side area facingthe latent heat unit 200B is formed to be greater than the width E2 ofthe side area opposite the latent heat unit 200B to secure a wider heattransfer area in a region in which heat exchange is actively performed.

Flow channels of the combustion gas and the heating medium in the heatexchanger 1 according to the present invention will be described below.

The flow channel of the combustion gas will be described first withreference to FIG. 14. In FIG. 14, arrows indicate a flow direction ofthe combustion gas.

The combustion gas generated by the combustion in the burner 100 flowsradially outward inside the combustion chamber C and passes through thesensible heat unit combustion gas flow channel P4 formed between theunit plates of the sensible heat unit 200A, and sensible heat of thecombustion gas is transferred to the heating medium passing through thesensible heat unit heating medium flow channel P3 while the combustiongas passes through the sensible heat unit combustion gas flow channelP4.

A combustion gas flowing downward via the sensible heat unit combustiongas flow channel P4 flows downward through the latent heat unitcombustion gas flow channel P2 formed between the unit plates of thelatent heat unit 200B, and latent heat of condensation contained inwater vapor of the combustion gas is transferred to the heating mediumpassing through the latent heat unit heating medium flow channel P1 topreheat the heating medium while the combustion gas flows downwardthrough the latent heat unit combustion gas flow channel P2.

Simultaneously, a combustion gas flowing upward via the sensible heatunit combustion gas flow channel P4 is discharged to the combustion gasbypass flow channel 400 a through the plurality of first combustion gasflow holes 203, and the combustion gas passing through the combustiongas bypass flow channel 400 a is supplied to the latent heat unitcombustion gas flow channel P2 through the plurality of secondcombustion gas flow holes 204.

Thus, the combustion gas flowing to an upper side of the combustionchamber C is redirected to be recovered by the latent heat unitcombustion gas flow channel P2 such that a loss of heat transferred tothe outside through the upper portion of the combustion chamber C can beprevented.

A combustion gas reaching a lower portion of the latent heat unitcombustion gas flow channel P2 passes through the plurality ofcombustion gas pass-through units D which are formed at the lowerportion of the latent heat unit 200B at regular intervals, and isdischarged downward. At this point, since the combustion gas isdistributed and discharged at a uniform flow rate across the entirelower area of the latent heat unit 200B due to the plurality ofcombustion gas pass-through units D formed at regular intervals, aphenomenon in which the combustion gas is biased to one side isprevented such that the flow resistance of the combustion gas can bereduced, and generation of noise and vibration can be also minimized.

The combustion gas passing through the plurality of combustion gaspass-through units D is discharged upward through the lower cover 310and the combustion gas discharge pipe 320, and condensation isdischarged through the condensation discharge pipe 311 connected to thelower portion of the lower cover 310.

The flow channel of the heating medium will be described below withreference to FIGS. 4 and 6. In FIGS. 4 and 6, arrows indicate a flowdirection of the heating medium.

The flow channel of the heating medium in the latent heat unit 200B willbe described first.

A heating medium flowing into the heating medium inlet 201 formed at thefirst plate 200 a-1, which is disposed at a front surface of theplurality of plates, sequentially passes through the first through-holeH1 and the fifth through-hole H5 formed at each of the plurality ofplates 200 b-1 to 200 a-12, which are stacked behind the first plate 200a-1, to flow toward the water housing cooling unit B provided betweenthe first plate 200 a-12 and the Second plate 200 b-12 of the unit plate200-12 disposed at the rearmost position. Further, some flow rate of theheating medium sequentially passing through the first through-hole H1and the fifth through-hole H5 passes through the latent heat unitheating medium flow channel P1 provided inside each of the unit plates200-1 through 200-11 in a parallel structure, sequentially passesthrough the second through-hole H2 and the sixth through-hole H6 whichare diagonally disposed with respect to the first through-hole H1 andthe fifth through-hole H5, respectively, and flows toward the waterhousing cooling unit B provided between the first plate 200 a-12 and thesecond plate 200 b-12.

As described above, since the heating medium flow channels of the latentheat unit 200B are provided in a multiple parallel structure, flowresistance of the heating medium passing through the latent heat unitheating medium flow channel P1 is reduced, and, since the latent heatunit heating medium flow channel P1 and the latent heat unit combustiongas flow channel P2 are alternately disposed to be adjacent to eachother, the heating medium passing through the latent heat unit heatingmedium flow channel P1 may be preheated by effectively absorbing latentheat of the water vapor contained in the combustion gas.

Next, the flow channel of the heating medium in the sensible heat unit200A will be described.

The heating medium which passes through the water housing cooling unit Babsorbs heat transferred to the rear side of the combustion chamber C,and then sequentially passes through a third through-hole H3 formed atthe first plate 200 a-12 of the twelfth unit plate 200-12 and thirdthrough-holes H3 and seventh through-holes H7 formed at the plates 200b-11 to 200 b-9 stacked in front of the twelfth unit plate 200-12.

Further, since the first blocked portions H3′ and H7′ are formed at theplates 200 a-9 and 200 b-8 stacked at the front side, some of theheating medium sequentially passing through the third through-holes H3and the seventh through-holes H7 and flowing into the sensible heat unitheating medium flow channel P3 formed at each of the unit plates 200-12to 200-9 branches off in both directions, flows in a direction towardthe fourth through-hole H4 and the eighth through-hole H8 which are eachdisposed to be diagonal to the third through-hole H3 and the sevenththrough-hole H7, and then sequentially passes through the fourththrough-hole H4 and the eighth through-hole H8 to flow to the frontside.

The heating medium which passes through the fourth through-hole H4 andthe eighth through-hole H8 of the plates 200 a-9 and 200 b-8sequentially passes through a fourth through-hole H4 and an eighththrough-hole H8 which are formed at each of the plates 200 a-8 to 200b-5 sequentially stacked in front of the plates 200 a-9 and 200 b-8.

Further, since the second blocked portions H4′ and H8′ are formed at theplates 200 a-5 and 200 b-4 stacked at the front side, some of theheating medium sequentially passing through the fourth through-holes H4and the eighth through-holes H7 and flowing into the sensible heat unitheating medium flow channel P3 formed at each of the unit plates 200-8to 200-5 branches off in both directions, flows in a direction towardthe third through-hole H3 and the seventh through-hole H7 which are eachdisposed diagonal to the fourth through-hole H4 and the eighththrough-hole H8, and then sequentially passes through the thirdthrough-hole H3 and the seventh through-hole H7 to flow to the frontside.

The heating medium which passes through the third through-hole H3 andthe seventh through-hole H7 of the plates 200 a-5 and 200 b-4sequentially passes through the third through-hole H3 and the sevenththrough-hole H7 which are formed at each of the plates 200 a-4 to 200b-1 sequentially stacked in front of the plates 200 a-5 and 200 b-4.

Further, since portions of the plate 200 a-1 disposed at the foremostposition and corresponding to the third through-hole H3 and the sevenththrough-hole H7 are blocked, some of the heating medium sequentiallypassing through the third through-holes H3 and the seventh through-holesH7 and flowing into the sensible heat unit heating medium flow channelP3 formed at each of the unit plates 200-4 to 200-1 branches off in bothdirections, flows in a direction toward the fourth through-hole H4 andthe eighth through-hole H8 which are each disposed diagonal to the thirdthrough-hole H3 and the seventh through-hole H7, and then sequentiallypasses through the fourth through-hole H4 and the eighth through-hole H8to be discharged through the heating medium outlet 202 formed at theplate 200 a-1 disposed at the foremost position.

FIG. 6 illustrates the above-described flow channels of the heatingmedium in the latent heat unit 200B and the sensible heat unit 200A as aunit of a plate group, and in the present embodiment, an example inwhich a first plate group 200-A, a second plate group 200-B, and a thirdplate group 200-C, which are each configured with a set of eight plates,are configured from the front side to the rear side, has been described,but the total number of stacked plates and the number of platesconstituting each of the plate groups in the present invention may bechanged and implemented.

As described above, since the flow channels of the heating medium in thesensible heat unit 200A are configured to be connected in series, theflow channel of the heating medium may be formed to be maximally longwithin a limited space of the sensible heat unit 200A such that heatexchange efficiency between the heating medium and the combustion gascan be significantly improved.

1. A heat exchanger comprising: a heat exchange unit (200) in whichheating medium flow channels through which a heating medium flows in aspace between a plurality of plates and combustion gas flow channelsthrough which a combustion gas combusted in a burner (100) flows arealternately formed to be adjacent to each other, wherein the heatexchange unit (200) is configured with a sensible heat unit (200A)configured to surround an outer side of a combustion chamber (C),configured with an area at one side of a plate, and configured to heatthe heating medium using sensible heat of the combustion gas generatedby the combustion in the burner (100); and a latent heat unit (200B)configured with an area at the other side of the plate and configured toheat the heating medium using latent heat of water vapor contained inthe combustion gas which undergoes heat exchange in the sensible heatunit (200A), and a flow channel cap (400) is coupled to a rear side ofthe sensible heat unit (200A) and configured to provide a flow channelof the combustion gas to allow a combustion gas which passes through acombustion gas flow channel formed at an upper portion of the sensibleheat unit (200A) to flow into a combustion gas flow channel of thelatent heat unit (200B).
 2. The heat exchanger of claim 1, wherein: aplurality of first combustion gas flow holes (203) are formed at theupper portion of the sensible heat unit (200A) to allow the combustiongas generated in the combustion chamber (C) to flow to the combustiongas bypass flow channel (400 a) formed between the sensible heat unit(200A) and the flow channel cap (400), and a plurality of secondcombustion gas flow holes (204) are formed at a lower portion of thesensible heat unit (200A) to allow the combustion gas which passesthrough the combustion gas bypass flow channel (400 a) to flow to thecombustion gas flow channel of the latent heat unit (200B).
 3. The heatexchanger of claim 1, wherein: the plurality of plates are formed bystacking a plurality of unit plates each having a first plate and asecond plate which are stacked, the heating medium flow channel isformed between the first plate and the second plate of the unit plate,and the combustion gas flow channel is formed between a second plateconstituting a unit plate disposed at one side of adjacently stackedunit plates and a first plate of a unit plate disposed at the other sidethereof.
 4. The heat exchanger of claim 3, wherein: the first plate isconfigured with a first plane portion (210); a first protrusion (220)protruding from one side of the first plane portion (210) to a frontside and having a first opening (A1) formed at a center of the firstprotrusion (220) to constitute the sensible heat unit (200A); and asecond protrusion (230) protruding forward from the other side of thefirst plane portion (210) to the front side and configured to form thelatent heat unit (200B), and the second plate is configured with asecond plane portion (250); a first recess (260) recessed from one sideof the second plane portion (250) to the rear side, configured to form asensible heat unit heating medium flow channel (P3) between the firstprotrusion (220) and the first recess (260), and having a second opening(A2) corresponding to the first opening (A1); and a second recess (270)recessed from the other side of the second plane portion (250) to therear side, and configured to form a latent heat unit heating medium flowchannel (P1) between the second protrusion (230) and the second recess(270).
 5. The heat exchanger of claim 4, wherein, when the first plateand the second plate are stacked, the first plane portion (210) and thesecond plane portion (250) are in contact with each other, and thesecond protrusion (230) and the second recess (270) are configured to bein comb shapes bent in opposite directions.
 6. The heat exchanger ofclaim 4, wherein: a plurality of first gap maintaining portions (222)protruding toward the combustion gas flow channel are formed at thefirst protrusion (220), and a plurality of second gap maintainingportions (262) are formed at the first recess (260) at positionscorresponding to the plurality of first gap maintaining portions (222)to protrude toward the combustion gas flow channel.
 7. The heatexchanger of claim 6, wherein a protruding end of each of the pluralityof first gap maintaining portions (222) and a protruding end of each ofthe plurality of second gap maintaining portions (262) are formed to bein contact with each other.
 8. The heat exchanger of claim 1, wherein:the plate has an upright structure such that the sensible heat unit(200A) is disposed at an upper portion and the latent heat unit (200B)is disposed at a lower portion, and the burner (100) is a cylindricalburner and is assembled by being inserted into a space of the combustionchamber (C) in a horizontal direction from a front surface thereof. 9.The heat exchanger of claim 1, wherein the plate constituting thesensible heat unit (200A) is formed such that a width of a side areafacing the latent heat unit (200B) is formed to be larger than that ofan area opposite the latent heat unit (200B).
 10. The heat exchanger ofclaim 1, wherein: the latent heat unit (200B) is configured with aheating medium inlet (201) into which the heating medium flows, and aplurality of latent heat unit heating medium flow channels (P1) formedbetween the plurality of plates in parallel thereto and configured tocommunicate with the heating medium inlet (201), and the sensible heatunit (200A) is configured with a heating medium outlet (202) throughwhich the heating medium flows, and a plurality of sensible heat unitheating medium flow channels (P3) formed between the plurality of platesand connected in series between the plurality of latent heat unitheating medium flow channels P1 and the heating medium outlet (202). 11.The heat exchanger of claim 10, wherein: a sensible heat unit combustiongas flow channel (P4) is provided between the sensible heat unit heatingmedium flow channels (P3), and a latent heat unit combustion gas flowchannel (P2) communicating with the sensible heat unit combustion gasflow channel (P4) is provided between the latent heat unit heatingmedium flow channels (P1).
 12. The heat exchanger of claim 10, wherein:through-holes (H1) and (H5) provided at one side of the latent heat unit(200B) and through-holes (H2) and (H6) provided at the other side, whichcommunicate with the plurality of latent heat unit heating medium flowchannels (P1), are diagonally formed at the latent heat unit (200B) toconnect the plurality of latent heat unit heating medium flow channels(P1) in parallel, and through-holes (H3) and (H7) provided at one sideof the sensible heat unit (200A) and through-holes (H4) and (H8)provided at the other side, which communicate with the sensible heatunit heating medium flow channels (P3), are diagonally formed at thesensible heat unit (200A) to connect the sensible heat unit heatingmedium flow channels (P3) in series.
 13. The heat exchanger of claim 12,wherein: a heating medium flowing into the sensible heat unit heatingmedium flow channel (P3) through the through-holes (H3) and (H7)provided at the one side thereof branches off in both directions andflows toward the through-holes (H4) and (H8) formed at the other side ina diagonal direction; and the heating medium flowing into the sensibleheat unit heating medium flow channel (P3) through the through-holes(H4) and (H8) branches off in both directions and flows toward thethrough-holes (H3) and (H7) formed at the one side in the diagonaldirection.
 14. The heat exchanger of claim 13, wherein first blockedportions (H3′) and (H7′) configured to guide the heating medium, whichflows into the sensible heat unit heating medium flow channel (P3)through the through-holes (H3) and (H7) provided at the one sidethereof, to flow toward the through-holes (H4) and (H8) formed at theother side in the diagonal direction, and second blocked portions (H4′)and (H8′) configured to guide the heating medium, which flows into thesensible heat unit heating medium flow channel (P3) through thethrough-holes (H4) and (H8) provided at the other side, to flow towardthe through-holes (H3) and (H7) formed at the one side in the diagonaldirection are formed at the sensible heat unit (200A).
 15. The heatexchanger of claim 12, wherein: first flanges (H3-1) and (H4-2)protruding toward the combustion gas flow channel are formed at thethrough-holes (H3) and (H4), respectively; and second flanges (H7-1) and(H8-1) protruding toward the combustion gas flow channel and in contactwith ends of the first flanges (H3-1) and (H4-2) are formed at thethrough-holes (H7) and (H8), respectively.